Crafting Question

[Thurbane]

According to the Body Slot Affinity section of the SRD, I would say Evasion either falls under protection (cloak, cape, mantle, amulet, brooch, medallion, necklace, periapt or scarab), physical improvement (shirt) or quickness (gloves). If your DM is OK with it, you should be able to make one of the above items of Evasion for the same price as the ring.

Alternatively, you could make in an unslotted item (maybe an Ioun Stone?) for double the usual cost.